Let NVDA process injected mouse events if desired

[LeonarddeR]

Steps to reproduce:

1. Using remote control software like TeamViewer, control the machine of an NVDA user
2. Move the mouse while the remote system has mouse tracking enabled

Actual behavior:

NVDA on the remote system doesn't echo what is under the mouse.

Expected behavior:

NVDA on the remote system echoes what is under the mouse.

Technical details

NVDA is simply ignoring injected mouse events. I propose a system that is similar to how injection is handled for the keyboard.

System configuration:

NVDA Installed/portable/running from source:

Both installed and running from source

NVDA version:

Latest next and master snapshots, but honestly, this isn't very relevant.

Windows version:

Windows 10 april update

Name and version of other software in use when reproducing the issue:

TeamViewer 10, ConnectWise Control Remote Support